请问哪位大牛看看是那里错了


#include <iostream>
#include <stack>


using namespace std;



struct Point
{
	int Indeg;
	int Outdeg;
};

Point Points[26];
bool isvisted[26];
bool way[26][26];



int main() 
{
	char temp[2000];
	int n;
	int m;
	cin>>n;
	while(n--)
	{
		int a=sizeof(way);
		for(int i=0; i<26; i++)
		{
			isvisted[i]=true;
			Points[i].Indeg=0;
			Points[i].Outdeg=0;
			for(int j=0; j<26; j++)
				way[i][j]=false;
		}
		cin>>m;
		while(m--)
		{
			cin>>temp;
			Points[temp[0]-'a'].Outdeg++;
			Points[temp[strlen(temp)-1]-'a'].Indeg++;
			way[temp[0]-'a'][temp[strlen(temp)-1]-'a']=true;
			isvisted[temp[0]-'a']=false;
			isvisted[temp[strlen(temp)-1]]=false;
			
		}
		bool isok=true;
		int begin=0;
		int end=0;
		for(int i=0 ;i<26; i++)
		{
			if(Points[i].Indeg==Points[i].Outdeg+1)
				end++;
			else if(Points[i].Indeg==Points[i].Outdeg-1)
				begin++;
			else if(Points[i].Indeg==Points[i].Outdeg)
				continue;
			else
			{
				isok=false;
				break;
			}
		}
		if(begin==0 && end==0 || (begin==1 &&end==1))
			isok=isok && true;
		else
			isok=false;
		if(!isok)
		{
			cout<<"The door cannot be opened."<<endl;
			continue;
		}
		stack<int> mystack;
		if(begin==0)
		{
			for(int i=0; i<26; i++)
			{
				if(isvisted[i]==false)
				{
					isvisted[i]=true;
					mystack.push(i);
					break;
				}
			}
		}
		else
		{
			for(int i=0; i<26; i++)
			{
				if(isvisted[i]==false && Points[i].Indeg==Points[i].Outdeg-1)
				{
					isvisted[i]=true;
					mystack.push(i);
					break;
				}
			}
		}
		while(!mystack.empty())
		{
			int mid=mystack.top();
			mystack.pop();
			for(int i=0; i<26; i++)
			{
				if(way[mid][i]==true && isvisted[i]==false)
				{
					isvisted[i]=true;
					mystack.push(i);
				}
			}
		}
		for(int i=0; i<26; i++)
		{
			if(isvisted[i]==false)
			{
				isok=false;
				break;
			}
		}
		if(isok)
			cout<<"Ordering is possible."<<endl;
		else
			cout<<"The door cannot be opened."<<endl;
	}
}